It is known that the technology for generating light by means of light emitting diodes (LED, Light Emitting Diode) provides for a very significant savings of energy compared to the other existing lighting technologies due to the fact that LED devices generate light from electrical energy with a higher yield in terms of lumens per watt and with higher quality in terms of chromic reproduction. At the same time, they have a longer service life than lights of the state of the art.
Due to the above-mentioned advantages, a great deal of development work has been done to improve various lighting applications using LED devices.
One of the possible applications is to use them in street lighting luminaries: Public areas in cities, public streets, parks, parking areas, etc.
The conventional way to undertake a street lighting project using LED technology is by installing new luminaries that are specifically designed for this technology, thereby replacing the conventional luminaries that existed previously. The reason why replacement is required is due to the specific thermal and optical requirements of the sources of LED light. The fact that it is necessary to replace the entire luminaries means that there is a very high cost that in many cases is not offset by the energy savings provided by the LED technology.
Numerous efforts have been made to solve this problem by adopting luminaries from technologies other than LED. The idea behind all these efforts was to develop a light built with LED technology that would make it possible to use it in an existing luminary by replacing the conventional light. These lights were therefore called LED replacement lights.
The problem of developing LED replacement lights for home lighting has been solved technically, and adequate commercial products exist.
For the field of street lighting, however, even though commercial LED replacement lights exist, they suffer from a number of deficiencies or drawbacks that limit many uses. The main issues standing in the way of developing a replacement LED light for street lighting are the following:
Conventional street lighting lights offer very high luminous flux values. Achieving equivalent values with LED devices requires an electric power that is much greater than that of home-use LED lights but is still smaller than that of conventional street lighting lights. Despite the high yield of LED technology, combined with the fact that such lights cannot operate at temperatures above 80° C. or 90° C. without losing yield and service life, and due also to the limitations that conventional lights have with respect to the evacuation of the heat generated inside them, it has not been possible to develop LED replacement lights for street lighting that are acceptably efficient and reliable.
Conventional lights for street lighting have light reflectors that are intended for lights that radiate omni-directionally. By their nature, LED devices radiate in a directional manner. This feature is advantageous for building specific LED luminaries since it avoids the use of light reflectors, but it is a drawback when it comes to building a replacement LED light.
In addition to the actual radiant LED device, LED technology requires the use of a power converter that adapts the supply voltage, usually alternating current, to the power required by LED semiconductor devices which, as we know, is direct current. Conventional luminaries do not require this kind of power converter, which has to be installed in the luminary or in the light itself; this latter option is the one that is most advantageous with regard to simplicity of installation, but it is the option that requires the power converter to operate under conditions of elevated temperature, making it difficult to do so reliably.
There are inventions that claim to solve the above-mentioned problems, but they do not do so satisfactorily or are not applicable to use in street lighting.
In this connection International Patent application WO2011/135151 can be cited, which describes a replacement light whose main drawback is the lack of dissipation devices that are sufficient to evacuate the heat to the outside. The dissipation devices that it presents are quite ineffective when they are confined in biconical housings with a minimal opening to the outside. Another drawback of these devices is the fact that the light that the LED devices emit is not radiated directly to the outside of the light, but rather cause it to be reflected at several conical metal reflectors that are likely to undergo oxidation and therefore experience impairment of their optical properties. Moreover, the above-described light does not have a built-in power adapter, and this makes it necessary to provide an external power adapter.
It is also possible to cite US patent application US2009/0267509, which describes a replacement light in which the LED radiant elements are confined inside a glass enclosure; this hampers the dissipation of the heat that is generated by the LED devices. The light is radiated in a single direction, which also makes this device unsuitable as a replacement light for street lighting.
US patent application US2010/0134046 can also be cited. This application describes an approach for adapting a conventional street-lighting light to LED illumination technology, but it cannot be regarded as a replacement light because it requires a great deal of manipulation in the luminary: it is not connected to the existing socket and requires additional mechanical anchoring devices.
US patent application US2011/0134239 describes a replacement light that radiates in just one direction, and therefore it cannot be used in luminaries that require omnidirectional lights. The dissipation element is not modular, but rather is made up of a single block that is arranged on a panel of LED devices, meaning that the useful surface area of the dissipation device is reduced. Moreover, the effectiveness of the dissipation device is greatly compromised by the location of the device: between the LED panel and the power supply, both of which block the movement of air by the dissipation device.
The document that comes closest to the invention is CN 202203704 U (QINZHENG HUANG), which describes an LED light for lighting that includes a base that is equipped with a fitting for attachment to the socket of a luminary and for electrical connection, and it also comprises an AC-DC power converter that is required for LEDs. The LED light described in this document also includes a number of heat dissipation modules that are mounted on the base in order to facilitate the cooling of the light. However, these modules are not configured to house along their periphery carrying cards for a number of LEDs, which makes it easier to incorporate them.
The document CN 202091825 U (DUJIANGYAN HUAGANG ELECTRONIC TECHNOLOGY CO LTD.), which was published on Dec. 28, 2011, describes the integration of a number of heat dissipation modules that are mounted on the base and are configured to attach around their periphery at least one card that carries a number of LEDs; in addition, these dissipation modules also comprise a number of cooling fins (FIG. 1), but this document does not call for the LED card to be mounted on contiguous dissipation modules, rather taking advantage of the actual mounts of these dissipation modules.
The invention provides a new configuration of the dissipation modules that makes it possible to mount the LED cards at the same time as when the dissipation modules are mounted; this simplifies fabrication.